1. Field of the Invention
The present invention relates to a dispersant slurry of at least one inorganic particulate, at least one dispersant, and at least one liquid amide and, more particularly, to such a slurry in which the dispersant is a modified phosphated poly(alkyleneether) alcohol.
2. Description of Background Art
Inorganic particulates are used as additives in making fibers, including solution-spun spandex. A variety of such additives are disclosed in U.S. Pat. Nos. 4,525,420, 3,389,942, and 5,626,960 and can be added to the spinning solution in the form of a mixture. Difficulties in filtering such solutions preparatory to spinning and deposits in the spinnerets can arise due to the presence of the inorganic particulates.
European Patent Application 558,758 and U.S. Pat. No. 5,969,028 disclose the use of fatty acids and metal salts of fatty acids as dispersants; however, these are not particularly effective. British Patent 1,169,352 and Japanese Published Patent Application JP63-151352 disclose the use of polyether phosphates, as dispersants for inorganic materials but not in liquids suitable for solution spinning of polyurethanes into spandex.
International Patent Application WO00/09789 and Japanese Published Patent Application JP11-229235 also disclose certain dispersants and selected additives in spandex to impart chlorine registance to polyurethane fibers. Both of these references disclose phosphoric acid esters (xe2x80x9ctreatment agentxe2x80x9d) combined with oxides or hydroxides of zinc, magnesium or aluminum. WO00/09789 requires, for producing elastomeric urethane fibers, that the metal particles adhere to the treatment agent. The treatment agent includes polyoxyalkylene glycol alkylene ether acid phosphates, among others. Slurries made with these dispersants are not sufficiently stable, especially at high levels of inorganic particulates.
There is still a need for improvements in spinning spandex containing inorganic additives.
The dispersant slurry of the present invention consists essentially of
(A) 10-78 wt %, based on the total weight of the dispersant slurry, of an inorganic particulate;
(B) 2-50 wt %, based on the inorganic particulate, of a dispersant soluble in the liquid of component (C) selected from the group consisting of
(i) phosphated block poly(alkylsiloxane) poly(alkyleneether) alcohols and
(ii) aromatic- or alkylaromatic-terminated phosphated poly(alkylene ether) alcohols; and
(C) a liquid selected from the group consisting of dimethylsulfoxide, tetramethylurea and amides.
The method of making spandex using the dispersant slurry of this invention comprises the steps of:
(A) milling the slurry so that the particulate has a median particle size no greater than about 5 microns;
(B) adding the slurry to a solution of polyurethane in a spinning solvent; and
(C) spinning the mixture from step (B) to form spandex.